36 five window interior panels

[Bruce_MO]

Google “upholstery panel board” and you’ll find what many people use. It’s waterproof and about $15 for a 32” x 48” sheet. I think it’ll be easier to to shape and cut than Masonite, and it’s a much closer duplicate to original panels. I always back it up with plastic sheet that I glue to the backside, because I’ve had issues with it warping slightly when water gets into the door.